JP3034152B2 - Control method of vacuum heating and drying equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system for a vacuum heating and drying apparatus, and more particularly to a vacuum system for drying garbage in a finite enclosed space such as a spacecraft, a submarine, and an aircraft, or at home or a restaurant. The present invention relates to a control method of a heating / drying apparatus, or a control method of a vacuum heating / drying apparatus for drying an organic substance (including food) or an inorganic substance at the above-mentioned place or the like.

[0002]

2. Description of the Related Art Conventional vacuum heating and drying apparatuses using microwaves are disclosed in JP-A-61-211201, JP-A-61-211202, and JP-A-62-1941.
No. 81, Japanese Patent Application Laid-Open No. 4-80585 discloses an apparatus.

In JP-A-61-211201 and JP-A-61-211202, an apparatus is started by a microswitch attached to a lid of a microwave shielding container (hereinafter, sometimes simply referred to as a container). Then, the magnetron is started when the vacuum gauge attached to the container becomes a predetermined pressure or less, and thereafter, the magnetron is turned on and off according to the detection information from the temperature detector in the vacuum pipe.
Had to be configured.

In Japanese Patent Application Laid-Open No. 62-194181, when the magnetron is turned on and off based on detection information from a temperature detector in a vacuum pipe, the magnetron is turned on and off.
If the time to F exceeds a certain value, the apparatus is configured to stop.

[0005] Further, in the above-mentioned Japanese Patent Application Laid-Open No. 04-080585, the vacuum exhaust is performed only by the inner container installed in the microwave shielding container.

[0006]

However, in the prior arts according to the prior applications described above, no consideration is given to leakage from the container, and even if a large amount of leakage occurs due to a hole or the like being opened in the container. There was a serious problem that the abnormality of the device could not be detected.

Further, in the above-described prior art, no consideration is given to empty cooking, and a state in which the object to be dried is not contained in the container or a state in which the object to be dried which has been completely dried from the beginning is put in the container. However, since the apparatus starts heating after reaching a predetermined degree of vacuum and does not stop the heating operation until the exhaust temperature reaches a predetermined value, there is a problem that the apparatus is overheated and is dangerous.

Further, in the above-mentioned prior art, no consideration is given to the heating efficiency of the magnetron, and when the temperature difference between the temperature at which the magnetron is stopped and the temperature at which it is restarted is large, the ratio of heating by the magnetron is reduced. There was a problem that was small.

The present invention has been made in view of the above points,
The purpose is to detect when a large amount of leak has occurred in a container and automatically stop the operation to prevent the failure from spreading.

Another object of the present invention is as follows.
While detecting the exhaust gas temperature, identify the state where there is no dried object in the container or the state where the dried object has been completely dried in the container from the beginning, that is, the state of empty cooking, and identify it as empty cooking In such a case, the safety is ensured by immediately stopping the device, and when the object to be dried containing water is contained, the device is operated until the normal end.

Still another object of the present invention is to increase the rate of heating by the magnetron and improve the processing speed.

[0012]

Means for Solving the Problems Among the above-mentioned objects, in order to achieve the detection of an abnormality of the apparatus when a large amount of leaks occur in the container and to prevent the expansion of the failure, the outside of the microwave shielding container is achieved. A pressure sensor is added to the vacuum exhaust pipe,
A timer is added to a control device that controls the entire vacuum heating and drying device, and the control device determines whether or not a leak has occurred based on information on a temporal change in the exhaust pressure, and determines each part according to the determination result. Is driven or stopped.

A temperature sensor is added to a vacuum exhaust pipe outside the microwave shielding container in order to distinguish between the empty cooking state and the normal state and to safely drive or stop the apparatus. In addition, a timer is added to the control device, and the control device determines whether or not there is an object to be dried containing moisture in the microwave shielding container according to information on a temporal change in the exhaust gas temperature. The configuration is such that each unit is drive-controlled or stopped according to the determination result.

Further, in order to make it easier to distinguish between the above-mentioned empty cooking state and the normal state, a heating number counter is added to the control device.

Further, of the above objects, in order to increase the rate of heating by the magnetron and improve the processing speed, the temperature difference between the temperature at which the magnetron is stopped and the temperature at which it is restarted is optimized. It was configured to be.

[0016]

[Function] By adding a pressure sensor to the vacuum exhaust pipe outside the microwave shielding container and adding a timer to the control device that controls the entire vacuum heating and drying device, the control device can be operated at the start vacuum exhaust operation (at the start ) And during vacuum evacuation operation with heating by a magnetron (during operation after the operation starts up), while monitoring changes in the pressure applied to the object to be dried in the container using information from a timer and a pressure sensor, the vacuum pump Can be operated. Then, the control device determines that the abnormality is abnormal when the pressure does not reach the predetermined pressure (does not decrease to the predetermined pressure) even after the lapse of the predetermined time during the evacuation operation at the start or during the evacuation operation accompanied by heating by the magnetron. At this time, in the case of the start evacuation operation, the control device immediately stops the operation of the entire device. If the evacuation operation with heating by the magnetron is being performed, the controller stops heating by the magnetron, continues evacuation for a predetermined period, and lowers the evacuation temperature when the evacuation temperature does not drop below a predetermined pressure. After that, the operation of the entire apparatus is stopped. Further, the control device displays a warning in each case. This allows
Even when the lid is closed, if a large amount of leakage occurs in the microwave shielding container, it can be detected as an abnormality. Therefore, it is possible to automatically stop the apparatus before the failures increase, and it is possible to prevent transmission of the failures.

Further, by adding a temperature sensor to the vacuum exhaust pipe outside the microwave shielding container and further adding a timer to the control device, after reaching a predetermined pressure, the control device receives the signal from the timer and the temperature sensor. The drive of the magnetron can be controlled while monitoring the change in the exhaust gas temperature based on the information. If the exhaust temperature does not rise even after the lapse of a predetermined time at the time of the initial heating, the control device determines that the temperature is abnormal, stops the magnetron, and then confirms that the exhaust temperature has become sufficiently low. The operation is stopped to stop the operation of the entire apparatus. Thereby, it is possible to recognize that the object to be dried containing water is not contained in the microwave shielding container (that is, to cook empty), to safely stop the device, and to display a warning.

On the other hand, after reaching the predetermined temperature, the control device controls the operation of the magnetron while monitoring a change in the exhaust gas temperature based on information from the timer and the temperature sensor.
In this case, the control device stops heating by the magnetron and time measurement by the timer when the exhaust temperature reaches the boiling point of water at the ultimate vacuum degree in the container, and the exhaust temperature is changed from the above boiling point temperature. After the temperature is lowered by the predetermined temperature difference, the heating by the magnetron and the time measurement by the timer are restarted. Further, in the case where the heating is not the first time, even after the elapse of a predetermined time after the magnetron is restarted, if the exhaust temperature does not reach the boiling point of water at the ultimate degree of vacuum in the container, it is determined that drying has been completed, and the magnetron is stopped. Then, the normal operation is displayed while evacuating, and after confirming that the exhaust temperature is sufficiently low, the operation of the entire apparatus is stopped.
As a result, it is possible to safely terminate the operation of the device.

Further, by adding the heating number counter to the control device, it is possible to determine whether or not the heating is the first heating, and the above-described control operation can be easily executed.

Further, a temperature at which the magnetron stops, and
By optimizing the temperature difference from the restarting temperature, the rate of heating by the magnetron can be increased, and the processing speed can be improved.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to each embodiment shown in FIGS. FIG. 1 is a configuration diagram of a control system of a vacuum heating and drying apparatus according to a first embodiment of the present invention. In the figure, 1 is an outlet, 2 is a main power switch operated by an operator, 3 is a DC power supply for a control circuit, 4 is a processing start switch operated by the operator, 5 is a processing stop switch operated by the operator, 6 Is a display device (for example, a CRT display,
A display unit 7 composed of an LCD display) has an exhaust pipe (vacuum pump 17) outside a container (microwave shielding container) not shown.
Pressure sensor installed in an exhaust pipe (a pipe to the vacuum pump 17) outside the container, 9 a thermostat for magnetron, 10 a thermostat for the container, and 11 and 11 a thermostat for the container. A lid limit switch as a lid open / close detection sensor for detecting the open / closed state of the lid of the container, 12 is a main power supply relay, 13 is a magnetron drive relay, 14 is a vacuum pump drive relay, 15 is a high voltage power supply for magnetron, and 16 is inside the container. A magnetron (microwave heater) for heating the material to be dried stored in the container, 17 is a vacuum pump for evacuating the inside of the container, and 18 is a magnetron cooling blower for cooling the magnetron 16. In addition, reference numeral 100 denotes a control circuit that controls the entire system (entire vacuum heating / drying apparatus).
An exhaust time measurement timer 21, a heating time measurement timer 22, and a heating number counter 23 are provided.

As shown in FIG. 1, the control circuit DC power supply 3
The main power relay 12 is connected to the outlet 1 via a main power switch 2 (if unnecessary, this can be omitted), and the control circuit power supply 3 is connected to the control circuit 100. The control circuit 100 includes a processing start switch 4, a processing stop switch 5, a pressure sensor 7, and a temperature sensor 8.
Are connected, and the control circuit 100 includes the components 4, 5, 7,.
8, operation input information and measurement information are received and recognized. Further, a display unit 6 is connected to the control circuit 100, and the display unit 6 displays a message according to a signal from the control circuit 100.

The control circuit 100 and the main power supply relay 12
The control circuit 100 is connected to a signal line via the lid limit switch 11 and one signal line now.
Recognizes the open / closed state of the lid by the lid limit switch 11 and turns on the main power supply relay 12 as necessary.
OFF control. The main power supply relay 12 is connected to a magnetron drive relay 13 and a vacuum pump drive relay 14, respectively. The magnetron drive relay 13 is connected to a magnetron 16 via a magnetron high voltage power supply 15, and the vacuum pump drive relay 14 is connected to a vacuum. Pump 1
7 and a magnetron cooling blower 18 respectively. The control circuit 100 and the magnetron drive relay 13 are connected to a signal line via the magnetron thermostat 9 and the container thermostat 10.
And the control circuit 10
0 recognizes the conduction state of the magnetron thermostat 9 or the container thermostat 10, and controls the magnetron drive relay 13 ON / OFF as needed. The control circuit 100 and the vacuum pump driving relay 1
4 is also connected, and the control circuit 100 controls ON / OFF of the vacuum pump drive relay 14 as necessary. In this embodiment, the vacuum pump driving relay 14
Is turned on, the vacuum pump 17 and the magnetron cooling blower 18 are driven together.
The vacuum pump 17 and the magnetron cooling blower 18 may be configured to be independently driven and controlled.

Further, the exhaust time measurement timer 21 and the heating time measurement timer 22 of the control circuit 100
The timing operation and the reset operation are controlled based on the control signal from the timer control unit as appropriate.
Measures the evacuation time by the vacuum pump 17 during a predetermined period, and the heating time measurement timer 22 measures the heating time of the magnetron every time the magnetron is started. The heating number counter 23 of the control circuit 100 is reset when the apparatus is started up, counts the number of transmissions of the control signal to the magnetron drive relay 13, and counts the number of times of heating by the magnetron.

In the above configuration, when the outlet 1 and the main power switch 2 are turned on, power is supplied to the control circuit power source 3 and the main power relay 12. As a result, the control circuit 100 is activated, and the apparatus (system) enters a standby state, and the control circuit 100 causes the display unit 6 to display a message indicating that the apparatus is in the standby state. By operating the processing start switch 4 in this state, the control circuit 100 is instructed to start control for performing vacuum heating and drying. As a result, the control circuit 100 executes the control processing according to the flow shown in FIG. Hereinafter, the operation of this embodiment will be described with reference to FIG.

When control start is instructed, the control circuit 100
First, the continuity of the signal line connected to the main power supply relay 12 from the lid limit switch 11 is checked (step ST1), thereby determining whether or not the lid is closed (step ST2). If it is open, this fact is displayed on the display unit 6 (step ST9), and the subsequent operations are stopped. Further, when it is confirmed in step ST2 that the lid is closed, the control circuit 100 sends a relay contact connection command to the main power supply relay 12 so that the main power supply relay 12 is first brought into a conductive state. Then, a relay contact connection command is sent to the vacuum pump drive relay 14 to make the vacuum pump drive relay 14 conductive, whereby the vacuum pump 17 and the magnetron cooling blower 18 are turned on.
To start the evacuation operation (step ST
3). Simultaneously with the start of the evacuation, the evacuation time measurement timer 21 of the control circuit 100 is started, and measurement of the time t from the start of the evacuation is started (step ST4).
Is reset (step ST).
5).

In the above state (after step ST5), the control circuit 100 monitors the exhaust pressure P from the workpiece measured by the pressure sensor 7 and the time t from the start of the exhaust by the exhaust time measuring timer 21. Then, it is determined whether or not the exhaust pressure P has reached a predetermined pressure P0 or less within a predetermined time t0 (steps ST7 and ST8). If not (NO), the container leak is large. Then, a command to open the relay contact is sent to the vacuum pump drive relay 14 to stop the evacuation operation (step ST8), and a message indicating a leak is displayed on the display unit 6 (step ST9). Stop the entire operation. That is, the fact that the exhaust pressure P does not reach the preset pressure P0 or less within the preset time t0 after starting the exhaust means that the inside of the container is evacuated with the lid closed. Nevertheless, this means that the intended decompression operation has not been achieved, and it can be determined that the leak from the container is large. Therefore, even when the lid is closed, if a large amount of leakage occurs in the container, this can be detected, this fact can be recognized by a message, and the device can be automatically stopped before the troubles increase.

On the other hand, in steps ST7 and ST8,
If it is confirmed that the pressure P measured by the pressure sensor 7 has reached the preset pressure P0 or less within the preset time t0, the control circuit 100
Sends a command to connect the relay contacts to the magnetron drive relay 13 to cause the magnetron 16 to start the heating operation via the magnetron high voltage power supply 15 (step ST).
10). Thus, the object is heated. By the start of this heating operation, the heating time measurement timer 22 of the control circuit 100 is started, and the time t 'from the start of heating is measured (step ST11). Heating times N
Is counted (step ST12). In this state, the control circuit 100 always performs the exhaust pressure P by the pressure sensor 7,
Exhaust temperature T and heating time measurement timer 2 by temperature sensor 8
2 while monitoring the time t ′ from the start of heating by Step 2 (Steps ST13 and S13).
T14, ST15).

That is, when it is determined in step ST13 that the pressure P has risen to the pressure P0 or more due to the start of heating (NO in step ST13),
The control circuit 100 interrupts the heating by the magnetron 16 (step ST16), and resets the contents of the exhaust time measurement timer 21 (step ST17).
Returning to step ST3, the operation is restarted from the exhaust start state. This is because, when a large amount of volatile components other than water vapor is generated from the material to be dried, the inside of the container needs to be depressurized again and then heated again from the beginning. If a leak occurs for some reason during the heating operation, after the heating is stopped, steps ST6 and ST7 are performed.
Is to detect a leak in the determination processing in step ST8, display a warning in the processing after step ST8, and to safely and automatically stop the apparatus (this is because of the following step ST8).
22 is the same).

Further, even when the pressure P is maintained at P0 or less by the start of heating (YES in step ST13), in steps ST14 and ST15, the exhaust gas temperature T is reduced to a predetermined time t1 from the start of heating.
If it is determined that the temperature does not reach the preset temperature T1 (see FIG. 3) within (see FIG. 3) (step ST
In the case of YES at 15), the heating is stopped (step ST28), and after confirming that the exhaust temperature is sufficiently low (step ST29), the exhaust by the vacuum pump 17 is stopped (step ST30). After that, the control circuit 1
00 indicates that the number of heatings N is 1 in step ST31.
(Initial heating)
In the case of (first heating), it is determined that the cooking is empty cooking in which the object to be dried is not contained in the container, and a message indicating that the cooking is empty cooking not including the object to be dried is displayed on the display unit 6 (step ST9) The operation of the entire apparatus is stopped. If the heating frequency N is 1 (initial heating), the fact that the exhaust gas temperature T does not reach the preset temperature T1 within the preset time t1 from the start of heating means that This is because the generated steam indicates that the exhaust gas temperature has not risen, and it is determined that empty cooking is performed. Therefore, the empty cooking state can be detected at the early stage of the operation start, the fact can be recognized by a message, and the device can be safely and automatically stopped.

On the other hand, if it is determined in steps ST14 and ST15 that the exhaust gas temperature T has reached the preset temperature T1 within the preset time t1 from the start of heating (YES in step ST14). Proceeds to step ST18, and the number of heating times N is 1
If N = 1, the heating setting time ta is set to t2 (see FIG. 3) (step ST19), and if N is 2 or more, the heating setting is performed. Time ta
Is set to t3 (see FIG. 3) (step ST20).
Then, the control circuit 100 sets the exhaust temperature T to the ultimate vacuum degree in the container within the set time t2 or t3 and in a state where the exhaust pressure P is lower than the preset pressure P0. It is determined whether or not the water has reached the boiling point temperature T0 in step ST2 (steps ST21 and ST2).
2, ST23). As a result of this determination processing, when the exhaust pressure P becomes equal to or higher than the preset pressure P0 (NO in step ST22), the control circuit 100 interrupts the heating by the magnetron 16 (step ST16) and measures the exhaust time. After resetting the contents of the timer 21 (step ST17), the process returns to step ST3 to restart the operation from the state of starting the exhaust.

Steps ST21, ST22, ST2
When it is determined by the determination process 3 that the exhaust gas temperature T does not reach the boiling point temperature T0 of water at the ultimate vacuum in the container within the set time (heating set time) t2 or t3 (step ST23). Is YES, the control circuit 100 stops the heating (step ST28),
After confirming that the exhaust gas temperature is sufficiently low (step ST2)
9), the evacuation by the vacuum pump 17 is stopped (step ST30). Then, after that, in step ST31, the control circuit 100 asks whether or not the number of heatings N is 1 (initial heating), and if the number of heatings N is 1 (in other words, the set heating setting When the time is t2)
Is determined to be empty cooking due to any of the factors described below, and a message indicating that the cooking is empty due to any of the factors is displayed on the display unit 6 (step ST
9) Stop the operation of the entire apparatus. What happens
When the number of heating times N is 1 (initial heating), the exhaust gas temperature T
However, the fact that the water does not reach the boiling point temperature T0 of the attained vacuum degree in the container within the set time t2 means that the object to be dried is not in the container but a small amount of water is in the container. In step ST14, ST14, there was almost no steam generated from the object to be dried, and the object to be dried was almost completely dried in the container, or the thermometer malfunctioned due to noise or the like. This is because it is possible to judge that the case is incorrect. Therefore, in addition to the empty cooking without the leak and the dried object, the empty cooking such as the drying object almost completely dried in the container is initially detected, and the fact that the operation is started early can be detected. Can be recognized by a message, and the device can be safely and automatically stopped.

On the other hand, steps ST21, ST22,
The heating time t2 set by the determination process in ST23.
Alternatively, if it is determined that the exhaust temperature T has reached the boiling point temperature T0 of water at the ultimate vacuum degree in the container within t3 (in the case of YES in step ST21), the control circuit 100
Determines that the heating operation has been performed normally for a predetermined period, and sends a command to open the relay contacts to the magnetron drive relay 13 to stop heating (step ST24). Then, after this, when it is confirmed that the exhaust gas temperature T has dropped to the temperature T2 (step ST25), the control circuit 100 resets the contents of the heating time measurement timer 22 (step ST26), and starts heating again. At the same time, the content (count value) of the heating number counter 23 is incremented by 1 (step ST27), and the process returns to step ST18. The magnetron 16 is turned ON-O by such an operation.
Heating / cooling is repeated by FF control. FIG. 3 shows a temporal change of the exhaust gas temperature T at this time. In FIG. 3, when the exhaust gas temperature increases with the passage of time, the magnetron 16 is ON, and when the exhaust gas temperature decreases with the passage of time, the magnetron 16 turns OFF.
State.

Here, as the drying of the material to be dried progresses, the time during which the magnetron 16 is in the ON state starts to gradually increase, and the ON time of the magnetron 16 rapidly increases at the end of the drying. For this reason, once the exhaust gas temperature T reaches the temperature T0, the heating time measuring timer 22 is reset every time heating is completed, and the heating number N of the heating number counter 23 is incremented by one. Set the heating time to t
3 and the time t 'from the start of turning on the magnetron 16 is measured each time. Then, the number of heating times N is 2 or more, in other words, the set time is t as described above.
3, when the above-mentioned steps ST21, S21
When the measurement time t ′ exceeds the heating set time t3 by the determination processing of T22 and ST23 (the above-described step ST23).
If the answer is YES), the control circuit 100 stops the heating (step ST28), and after confirming that the exhaust gas temperature is sufficiently low (step ST29), the vacuum pump 17
Is stopped (step ST30). After that, the control circuit 100 proceeds to step S as described above.
At T31, it is asked whether the number of heatings N is 1 (initial heating). In this case, the number of heatings N is 2 or more. Is displayed after the completion of the process (step ST3).
2) Stop the operation of the entire apparatus and end a series of processing. By such a process, it is possible to cause the device to execute the drying process and safely terminate the operation.

During the above-described processing, the pressure P
However, when the pressure rises to the pressure P0 or more, the heating is interrupted in any case, and the operation is restarted from the state of starting the exhaust. Further, when the magnetron 16 or the microwave shielding container is detected to be overheated by the magnetron thermostat 9 or the container thermostat 10, the magnetron 16 is immediately turned off,
Interrupt heating. When the lid limit switch 11 detects that the lid has been opened, the operation of the entire apparatus is stopped at that time. The two lid limit switches 11 are used as those having the functions of the processing start switch 4 and the processing stop switch 5 (the lid limit switch 11 for detecting closure of the lid is used as the processing start switch 4 and the opening of the lid is performed). Can be used as the processing stop switch 5). Further, one of the lid limit switches 11 can be used instead of the main power supply relay 12, and the other one of the lid limit switches 11 can be directly connected to the control circuit 100.

The control circuit 100 is a control circuit using a microprocessor, a control circuit using a comparator and a logic circuit, a control circuit using a thermometer with a temperature contact and a relay circuit, or a mixed circuit thereof. Can be configured. Further, as the temperature sensor 8, any sensor such as a thermocouple, a resistance temperature detector, a thermistor, and a thermostat can be used in combination with the control circuit 100 as long as it can generate a temperature signal or a temperature contact signal. It is. Also, the pressure sensor 7 may be any type that generates either a pressure signal or a pressure contact signal, such as a semiconductor pressure sensor, a strain gauge pressure sensor, a spring-type pressure sensor, and a pressure switch. Can be used.

As described in detail above, according to the present embodiment, a large leak is generated in the container, or the container is in an empty cooking state in which no material to be dried is contained. It is determined that the material to be dried, which has been almost completely dried, is in an empty cooking state from the beginning, and when the occurrence of these abnormalities is identified, the device is quickly stopped to ensure safety and to reduce the situation. An appropriate message can be displayed, and if there is no abnormality, the apparatus is operated until normal termination, so that a highly safe vacuum heating and drying apparatus can be realized.

Here, FIG. 3 described above simulates a change in the exhaust gas temperature predicted in an actual apparatus. The exhaust gas temperature is substantially equal to the temperature of water contained in the material to be dried when the water vapor in the exhaust gas evaporates. During heating, as the temperature increases, the vapor pressure of water at that temperature increases. As a result, the evaporation of water is activated, so that a large amount of latent heat of evaporation flows out together with the steam, and the temperature of the remaining water gradually rises. In addition, after heating is completed, since there is no heat source, the evaporation of water, which was initially actively performed, decreases due to the decrease in the amount of evaporation due to the decrease in temperature (accordingly, the decrease in vapor pressure of water). Becomes gradual. For this reason, as shown in FIG.
The temperature change in each heating state and each cooling state when heating-cooling is repeated has the largest rate of change at the start of each state, and decreases with time. Therefore, the ratio during the heating by the magnetron 16 is increased by reducing the temperature control width so that the temperature change indicated by the broken line is not the temperature change indicated by the solid line in FIG. That is, after the heating is stopped, when the exhaust gas temperature T drops to T2 ', the heating is restarted, so that the ratio during heating by the magnetron 16 can be increased.

It is obvious to those skilled in the art that the above-described control processing can be easily performed by making the determination at step ST25 in FIG. 2 T ≦ T2 ′. If the temperature control width is reduced in this manner, the rate of heating by the magnetron 16 can be increased, so that the drying processing speed can be improved.

In the first embodiment described so far, the number of times the magnetron 16 is turned on and off is measured, and it is determined whether the number of times of heating is the first time. Set the heating time to t
The method was changed to 2 or t3, and a method of distinguishing between the empty cooking and the end of the processing was adopted. However, by comparing the measured heating time t ′ with three parameters t1, t2, and t3 without measuring the number of times of heating, it is also possible to distinguish between the empty cooking and the end of the processing. Next, the heating time t ′ is set to t1,
By comparing the three parameters t2 and t3, the embodiment in which the empty cooking and the processing end are distinguished from each other,
This will be described with reference to FIGS.

FIG. 4 is a block diagram of a control system of a vacuum heating and drying apparatus according to a second embodiment of the present invention. This embodiment differs from the first embodiment in FIG. 1 in that the heating number counter 23 of the control circuit 100 is eliminated from the configuration in FIG.
FIG. 5 shows a control processing flow executed by the control circuit 100 according to the present embodiment.
The processing related to the processing of determining the number of times of heating in the processing flow of (1) is deleted, and the heating time t ′ is changed to t1, t2, and t3.
Processing operation to compare with two parameters is added.

As shown in FIG. 5, when control start is instructed, the control circuit 100 first sets the lid limit switch 1
1 to check the open / closed state of the lid (step ST5).
1) It is determined whether or not the lid is closed (step ST52). If the lid is open, this is displayed on the display unit 6 (step ST58), and the subsequent operations are stopped. . Further, when it is confirmed in step ST52 that the lid is closed, the control circuit 100 sends a relay contact connection command to the main power supply relay 12 so that the main power supply relay 12 is first brought into a conductive state. Then, a relay contact connection command is sent to the vacuum pump driving relay 14 to make the vacuum pump driving relay 14 conductive, whereby the vacuum pump 17 and the magnetron cooling blower 1 are turned on.
8 to start the evacuation operation (step S
T53). At the same time as the evacuation, the control circuit 10
The zero evacuation time measurement timer 21 is started, and starts measuring the time t from the start of evacuation (step ST54).

In the above state (after step ST54), the control circuit 100 monitors the exhaust pressure P and the time t from the start of the exhaust, and sets the exhaust pressure P within the preset time t0 within the preset time t0. It is determined whether the pressure has reached the pressure P0 or less (steps ST55 and ST5).
6) If no (NO) is determined, it is determined that the container leak is large, the evacuation operation by the vacuum pump 17 is stopped (step ST57), and a message indicating a leak is displayed on the display unit 6 (step ST57). Step ST58), the operation of the entire apparatus is stopped.

On the other hand, in steps ST55 and ST56, when it is confirmed that the pressure P has reached the preset pressure P0 or less within the preset time t0, the control circuit 100 causes the magnetron 16 to heat the magnetron 16. The operation is started (step ST59). By the start of this heating operation, the heating time measurement timer 22 of the control circuit 100 is started, and starts measuring the time t 'from the start of heating (step ST60). In this state, the control circuit 1
00 always performs a predetermined determination process while monitoring the exhaust pressure P by the pressure sensor 7, the exhaust temperature T by the temperature sensor 8, and the time t 'from the start of heating by the heating time measurement timer 22 (steps ST61 and ST62). ,
ST63).

That is, when it is determined in step ST62 that the pressure P has risen to the pressure P0 or more due to the start of heating (NO in step ST61),
The control circuit 100 interrupts the heating by the magnetron 16 (step ST64), and resets the contents of the exhaust time measurement timer 21 (step ST65).
Returning to step ST3, the operation is restarted from the exhaust start state.

Further, even when the pressure P is maintained at P0 or less by the start of heating (YES in step ST61), in steps ST62 and ST63, the exhaust gas temperature T is increased by a predetermined time t1 from the start of heating.
If it is determined that the temperature does not reach the preset temperature T1 (see FIG. 3) within (see FIG. 3) (step ST
In the case of YES at 63), the control circuit 100 determines that the cooking is the empty cooking in which the object to be dried is not contained in the container. Then, by this, the control circuit 100 stops heating (step ST75), confirms that the exhaust temperature is sufficiently low (step ST76), and then stops the exhaust by the vacuum pump 17 (step ST77). After the message indicating that the cooking is empty is displayed (step ST58), the operation of the entire apparatus is stopped.

On the other hand, if it is determined in steps ST62 and ST63 that the exhaust gas temperature T has reached the preset temperature T1 within the preset time t1 from the start of heating (YES in step ST62). In other words, the control circuit 100 sets the exhaust temperature T to a value at the ultimate vacuum degree in the container within the preset time t2 and in a state where the exhaust pressure P falls below the preset pressure P0. Is determined to have reached the boiling point temperature T0 (steps ST66, ST67, ST67).
ST68). As a result of this determination processing, when the exhaust pressure P becomes equal to or higher than the preset pressure P0 (step ST
If NO in step 67), the control circuit 100 interrupts the heating by the magnetron 16 (step ST).
64) After resetting the contents of the exhaust time measurement timer 21 (step ST65), the process returns to step ST53 to restart the operation from the state of starting the exhaust.

Steps ST66, ST67, ST6
When it is determined that the exhaust temperature T does not reach the boiling point temperature T0 of water at the ultimate vacuum degree in the container within the preset heating time t2 by the determination process of No. 8 (in the case of YES in step ST68) In the control circuit 100,
It is determined that the cooking is empty due to any of the above factors. Then, by this, the control circuit 100 stops heating (step ST75), confirms that the exhaust temperature is sufficiently low (step ST76), and then stops the exhaust by the vacuum pump 17 (step ST77). After displaying a message indicating that it is empty cooking (step S
T58) The operation of the entire apparatus is stopped.

On the other hand, steps ST66, ST67,
The heating time t2 set by the determination process of ST68
It is determined that the exhaust temperature T has reached the boiling point temperature T0 of water at the ultimate degree of vacuum in the container within (step ST
In the case of YES at 66), the control circuit 100 determines that the heating operation has been performed normally for a predetermined period, and stops heating by the magnetron 16 (step ST69). After that, the control circuit 100 determines that the exhaust gas temperature T is equal to the temperature T2.
When it is confirmed that the temperature has decreased to (or T2 ′) (step ST70), the content of the heating time measurement timer 22 is reset (step ST71), and the heating is restarted (step ST72). Then, it is determined whether or not the exhaust gas temperature T has reached the boiling point temperature T0 of the water at the ultimate degree of vacuum in the container (step ST73). If YES in step ST73, the process returns to step ST69 to perform heating. Is stopped, and the magnetron 16 is turned ON-O by this loop.
Heating and cooling are repeated by FF control.

If NO in step ST73,
After confirming that the exhaust pressure P does not exceed the preset pressure P0 (step ST74), in step ST78, the measurement time t 'from the restart of the heating is set to the preset heating set time t3 (or t3'). Is determined. If NO in step ST78, the process returns to step ST73. On the other hand, if YES in step ST78, the control circuit 100 determines that drying of the object to be dried is completed, and stops heating (step S78).
T79) After confirming that the exhaust temperature is sufficiently low (step ST80), the exhaust by the vacuum pump 17 is stopped (step ST81), and a message indicating that the drying is completed is displayed on the display unit 6 (step ST82). Then, the operation of the entire apparatus is stopped, and a series of processing is ended.

As described above, in the present embodiment, in the first heating after the start of evacuation, the measurement time t 'is compared with the time t1 until the evacuation temperature T reaches T1, and the measurement time t By comparing 'with the time t2 until the temperature T reaches T0, the empty cooking (the empty cooking in a state where there is no matter to be dried or moisture at all, and the above-described factors,
Is detected respectively. Further, once the exhaust gas temperature T reaches T0, the heating time timer 22 is reset when the exhaust gas temperature T cools down to T2. After the heating is resumed, the heating time timer 22 is reset until the measured time t 'and the temperature T reach T0. By comparing the time t3 with the time t3, the end of the process is detected. Thus, also in the present embodiment, it is possible to determine the completion of the empty cooking and the drying similarly to the first embodiment.

As described above, according to the present embodiment, the number of parts is reduced by eliminating the number-of-times-of-heating counter 23.
This has the effect of improving reliability.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 6 is a configuration diagram of a control system of the vacuum heating and drying apparatus according to the third embodiment of the present invention. As shown in FIG. 6, in this embodiment, the main power switch 2 is omitted from the configuration of the second embodiment shown in FIG. 4 (it can be easily realized). Further, the main power supply relay 12 and the signal lines connected to the main power supply relay 12 in FIG.
Accordingly, the main power supply relay 1
The lid limit switch 11 added to the signal line connected to the control line 2 is changed to a signal line for the magnetron drive relay 13 from the control circuit 100 and a signal line for the vacuum pump drive relay 14 from the control circuit 100, respectively. , At least one connection at a time. In addition, the pressure sensor 7 in FIG. 4 is omitted, and a pressure switch 71 (a switch that becomes conductive when P <P0) and a current sensor 72 are connected to two signal lines from the control circuit 100 to the magnetron drive relay 13. Each was connected.

In this embodiment, since the pressure switch 71 does not pass through the control circuit 100, the operation after the start of evacuation cannot measure the time until the pressure P0 is reached. For this reason, the control circuit 100 keeps generating a relay contact connection command to the magnetron drive relay 13 at all times, and the measurement of the time t by the exhaust time measurement timer 21 is performed instead of the time until the pressure P0 is reached. It is measured by the time until the energization of the sensor 72 is started. This corresponds to P in FIG.
<P0 can be achieved by replacing I ≠ 0. On the other hand, since the pressure switch 71 does not pass through the control circuit 100, it is possible to directly control the relay contact connection command to the magnetron drive relay 13 when the pressure is about P0. The operation of each unit other than the above is the same as the operation of the second embodiment shown in FIGS.

In this embodiment, similarly to the first embodiment shown in FIG. 1, the lid limit switches 11, 1 are provided.
1 can be used in place of the processing start switch 4 and the processing stop switch 5. In addition, in the configuration of the present embodiment shown in FIG. 6, the main power switch 2, the main power relay 12, and the signal lines connected to the main power relay 12 are installed in the same arrangement as the second embodiment in FIG. Can be easily realized. Further, conditions for the control circuit 100 and the temperature sensor 8 are the same as those in the first embodiment shown in FIG. Further, also in the present embodiment, it is possible to add the heating number counter 23 to the control circuit 100 as in the first embodiment of FIG. This case can be achieved by replacing P <P0 in FIG. 2 with I ≠ 0.

According to the third embodiment shown in FIG. 6, the pressure switch 71 directly cuts off the magnetron drive relay 13 without passing through the control circuit 100, so that the safety for temperature control at the time of pressure increase is improved. There is an effect of doing.

Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 7 is a configuration diagram of a control system of a vacuum heating and drying apparatus according to a fourth embodiment of the present invention. As shown in FIG. 7, this embodiment is different from the configuration of the second embodiment shown in FIG. 4 in that the main power supply relay 12, the signal line connected to the main power supply relay 12, the magnetron thermostat 9, and the container thermostat 10 The magnetron temperature sensor 91 and the container temperature sensor 101 connected to the control circuit 100 are provided instead of the magnetron thermostat 9 and the container thermostat 10 in FIG. Further, the lid limit switch 11 in FIG. 4 is connected to the control circuit 100, and all the states are managed by the control circuit 100. In such a configuration, the magnetron temperature sensor 91 and the container temperature sensor 101 can be of the same type as the temperature sensor 8.

The operation of the present embodiment shown in FIG. 7 is the same as that of the first embodiment shown in FIG. 1 except that the control circuit 100 directly controls all the components.

In this embodiment, similarly to the first embodiment shown in FIG. 1, the lid limit switch 11 can be used in place of the processing start switch 4 and the processing stop switch 5. Also, the main power switch 2 can be omitted from the present embodiment shown in FIG. 7 by adding a main power relay 12 and a signal line connected to the main power relay 12 similarly to the second embodiment shown in FIG. Installation can also be easily realized.
Further, conditions for the control circuit 100, the pressure sensor 7, and the temperature sensor 8 are the same as those in the first embodiment shown in FIG. Further, as in the first embodiment shown in FIG. 1, a heating frequency counter 23 can be added to the control circuit 100.

In the present embodiment, since all state data are collected in the control circuit 100, there is an effect that a judgment circuit for judging each state data in combination is simplified or simplified.

In each of the embodiments described above, any power source can be used as long as it can drive the magnetron and the vacuum pump. The main power supply relay 12, the magnetron drive relay 13, the vacuum pump drive relay 14,
In addition to a mechanical relay, a semiconductor relay, etc., any device that is suitable for the power supply used and that functions as a switch that opens and closes by an external signal can be used. Further, the exhaust time measurement timer 21 and the heating time measurement timer 22 can be shared by one timer. Further, instead of the lid limit switch 11, a rotation detection sensor or the like attached to a portion that rotates when the lid is opened and closed can be used. Also, the control flow is not limited to the control flow shown in FIG. 2 or FIG. 5, and any control flow can be used as long as control equivalent to a series of processing operations in each embodiment can be performed. It is.

[0062]

As described above, according to the present invention, by monitoring the time-dependent changes in the pressure and exhaust temperature in the container, it is possible to prevent the container from leaking or emptying (there is no object to be dried in the container). Or that the dried object has been completely dried in the container from the beginning), and the safety can be ensured by automatically stopping the device immediately if it is determined to be abnormal. In addition, when the object to be dried containing water is contained in the container, the apparatus is operated until normal termination, so that a highly reliable vacuum heating and drying apparatus can be realized, and its value is great.

Further, by reducing the control temperature range, the ratio of heating by the magnetron can be increased, so that there is an advantage that the processing speed can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of a control system of a vacuum heating and drying apparatus according to a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating a control processing flow executed by a control circuit of FIG. 1;

FIG. 3 is an explanatory diagram showing an example of a change in exhaust gas temperature due to a vacuum heating and drying operation in each embodiment of the present invention.

FIG. 4 is a configuration diagram showing a configuration of a control system of a vacuum heating and drying apparatus according to a second embodiment of the present invention.

FIG. 5 is a flowchart showing a control processing flow executed by the control circuit of FIG. 4;

FIG. 6 is a configuration diagram showing a configuration of a control system of a vacuum heating and drying apparatus according to a third embodiment of the present invention.

FIG. 7 is a configuration diagram illustrating a configuration of a control system of a vacuum heating and drying apparatus according to a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outlet 2 Main power switch 3 Power supply for control circuit 4 Processing start switch 5 Processing stop switch 6 Display part 7 Pressure sensor installed in exhaust pipe 8 Temperature sensor installed in exhaust pipe 9 Thermostat for magnetron 10 Thermostat for container 11 Lid limit Switch 12 Main power relay 13 Magnetron drive relay 14 Vacuum pump drive relay 15 High voltage power supply for magnetron 16 Magnetron 17 Vacuum pump 18 Magnetron cooling blower 21 Exhaust time measurement timer 22 Heating time measurement timer 23 Heating frequency counter 71 Pressure switch 72 Current sensor 91 Temperature sensor for magnetron 100 Control circuit 101 Temperature sensor for container

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F26B 25/00 F26B 3/347 F26B 5/04

Claims (4)

(57) [Claims] 1. A microwave shielding container for storing an object to be dried, a vacuum pump for evacuating the inside of the microwave shielding container, and a magnetro for heating the object to be dried in the microwave shielding container. and down, provided to the microwave shielding container out of the exhaust pipe, by adding a temperature sensor and a pressure sensor, further,
A timer is added to a control device that controls the overall control of the entire vacuum heating and drying device.If the control device is determined to be abnormal based on information from the temperature sensor, the pressure sensor, and the timer, the operation is stopped. True to stop
A control method of an air heating / drying apparatus, wherein the control apparatus starts before driving the magnetron.
During dynamic evacuation and heating by the magnetron
During the evacuation operation accompanying the operation, the timer and the pressure
The object to be dried in the microwave shielding container
Drive the vacuum pump while monitoring the pressure change
Control, and if the specified pressure is not reached even after the specified time elapses,
It is judged to be abnormal, and the equipment is immediately
Stop the operation of the entire device and display a warning,
In addition, vacuum evacuation accompanied by a heating operation by the magnetron
If the magnetron is in operation,
Stop and then continue evacuation for a specified period of time.
After lowering the temperature, stop the evacuation and
Stop driving operation and display a warning.
Characteristic control method of vacuum heating and drying equipment. 2. The control device according to claim 1, wherein the control device controls the timer and the timer after reaching a predetermined pressure.
Drying in the microwave shielding container by the temperature sensor
Monitor changes in the exhaust temperature of water vapor generated from objects
Drive control of the magnetron from the
The exhaust temperature does not rise to the predetermined temperature even after the predetermined time has elapsed.
The magnetron is stopped.
After confirming that the exhaust temperature is low enough,
Stopping the exhaust and stopping the operation of the entire system
Warning display on the vacuum heating and drying apparatus.
Control method. 3. The control device according to claim 2, wherein the control device is configured to operate after the predetermined pressure and the predetermined temperature are reached.
Then, the change of the exhaust gas temperature by the timer and the temperature sensor.
Control of the magnetron while monitoring the
Water at the ultimate vacuum in the microwave shielding container
When the boiling point temperature of the magnetron is reached,
Stop heating and time measurement by the timer, and
After a predetermined temperature difference from the boiling point
Heating by magnetron and time measurement by timer
Of vacuum heating and drying equipment characterized by restarting
Control method. 4. The apparatus according to claim 3, wherein the control device is configured to perform the heating when the heating is not performed for the first time.
Even after a certain period of time has passed after restarting the
Boiling point temperature of water at ultimate vacuum in the microwave shielding container
If the temperature is not reached, it is determined that drying is complete and the magnet
Shut down and then make sure the exhaust temperature is low enough.
After that, stop the evacuation and stop the operation of the entire system.
Stop and display the end of drying.
Control system for vacuum heating and drying equipment.